KN

KIN 343 - 10.9 Copper Excretion

Copper Excretion

  • Copper is essential for various biological functions but must be regulated to prevent toxicity.

Mechanism of Excretion

  • Copper Excretion Process: 95% of copper is excreted into the bile.

    • Bile produced by the liver plays a crucial role in copper removal from the body.

    • It is excreted into the gastrointestinal tract, facilitating direct copper elimination.

  • Regulation of Biliary Copper Excretion:

    • The body maintains copper balance by regulating biliary copper excretion.

    • If there is an excess of copper in the body, additional copper is pumped from the liver into synthesized bile.

    • This mechanism serves to manage copper levels and prevent overload.

Role of the Enzyme/Transporter

  • The transporter responsible for mediating the excretion of copper from the liver to bile is ATPA7B.

    • This transporter operates in an ATP-dependent manner.

    • It functions after copper has entered the body, specifically for excretion purposes.

  • Comparison to ATPA7A:

    • ATPA7A is found on enterocytes and plays a role in the initial absorption of copper during digestion.

    • ATPA7B, in contrast, is involved in the removal of excess copper from the body.

Summary

  • Effective copper regulation is crucial for health; the liver's role via bile synthesis and ATPA7B transporter is essential for preventing copper accumulation.